(Ehlers, 1864)
Description:
A scale-worm with a body of uniform width. Dorsal and ventral surfaces smooth.
Prostomium bilobed without peaks, with a median antenna, a pair of lateral antennae and a pair of palps. Two pairs of eyes, the anterior pair on the line of greatest width, the posterior pair in front of the rear margin.
First segment bearing chaetae and a pair of dorsal and ventral tentacular cirri. Scales overlap almost covering the body. Scales are oval to round with smooth margins and surfaces with small tubercles.
Notopodia are small mounds with a ventral acicular ligule and few chaetae. Notopodial chaetae flat with rows of prominent spines and blunt tips. Neuropodia well developed with an anterior acicular ligule. Neuropodial chaetae with a cusp at the base of the rows of spines, and a bidentate tip (A. pellucida-detail).
Size:
Up to 32 mm for 40 chaetigers.
Colour:
Yellowish dorsally, with dark markings.
Habitat:
Littoral and sublittoral, often associated with star-fishes, brittle-stars and feather stars.
Distribution:
Pacific, Indian Ocean, Atlantic to Mediterranean, Red Sea and Bosporus, English Channel and North Sea.